OP129: Report on Testing of Secondary Backflow Prevention DeviceUse this form to report the test that is required on all Internal (secondary) Backflow devices. Secondary devices are RPZ’s or Backflow’s used for cooling towers, boilers, medical equipment, etc. These secondary backflow devices are recorded by DOB not DEP. The LMP completes section one (1) and three (3) and the certified tester completes section two (2). No P.E. or R.A. is necessary on this form.